Rega RB900 Counterweights

Posted by: Tony L on 04 January 2001

Can anyone shed any light on the available counterweights from Rega for the RB900? Especially how to identify them.

At the end of the Hutterly Amazing thread, just before some regrettable name calling etc set in, Ron suggested that Vuk, Kevin, and myself might not actually be using the correct (i.e. heaviest) counterweight for our RB900 / XX1L on our P9s. There is a picture of Vuk's deck on the above where the counterweight we all use is clearly visible. Ross B has a heavy Rega counterweight for his RB300 which he states is visibly different to ours. I simply do not have sufficient knowledge of Rega products to interpret these different findings.

We all bought our weights from the same reputable source, the dealership Frank A works for on a Saturday, this is a very respected Naim / Rega dealership, and my questions here are absolutely not intended as any slur or question about the integrity or knowledge of that dealership - they have proved very knowledgeable and helpful in any dealings I have had with them. I would however like to establish whether we do have the heaviest available weight, as if not I want one!

Perhaps the easiest way of establishing this would be to find the physical weight of the available Rega weights, and then weigh one of ours to find out which it is. The one we have has a machined groove around the circumference, and sits right at the back of it's usable travel to balance the 12 gram XX1L. It is slightly heavier than the one that comes as standard with the RB900.

Tony.

Posted on: 04 January 2001 by Tony L

quote:
I understand that some OEM Rega arms use lesser quality stainless steel counterweights, and this may be what is being supplied by some dealers.

Ross,

Thanks for weighing your counterweight, perhaps Vuk or Kevin have their crack scales handy to weigh theirs - I only buy in kilos, so my bathroom scales are no good.

The counterweight I have would appear to be made of the same tungsten as the original one supplied with the RB900. I have seen the current RB300 weight, and that would appear to be different to either of my weights.

As I understand it, the RB300 weight was made from a cheaper material at some point later on in its life span - the weight I had with my 1986 RB300 on my old Xerxes from memory looks the same as the one that ships with the RB900, it definitely does not look like a current RB300 one.

The point is that I suspect the weights are now a different design for the RB300 and the RB900 arms. I suspect the RB900 has tungsten and the RB300 now uses the cheaper stainless steel design. What age is your arm, and what material are your weights made of?

My gut feeling is this is there are far more different weights than I first thought. Age and arm model is probably a big factor. I am only really interested in current Rega manufactured weights for the RB900 arm, though as a side issue I am slightly curious about the third party 'Heavy Weight' thing from Express Machining. I would like to hear one.

Tony.

Posted on: 04 January 2001 by Frank Abela

Gentlemen,

Sorry about being away so long.

I believe Tony has the heavy tungsten counterweight. This is because he describes it similarly to Vuk's. Now Vuk has both standard and heavy counterweights so he should be able to do a direct comparison, but looking at the (very nice) photo would indicate that to be the heavy weight.

The 300 is supplied as standard with stainless steel counterweight. The 600 and 900 are supplied as standard with a tungsten weight with no groove in the circumference.

To put the record straight:

The heavy counterweight has come in two versions. They're both made of tungsten. The earlier one was a little longer to look at, though perhaps not as large a circumference (can't recall). The new one coming out of the factory now has the groove in it. This is a unique feature of the new heavy counterweight, none having had grooves in the past.

Regards,
Frank.

Posted on: 04 January 2001 by Joe Petrik

Tony,

Did you remember to check which phono boards you're running, or did the crack dust on your counterweight take the evening in a different direction?

Joe

Posted on: 04 January 2001 by Frank Abela

RB300's used to come with a tungsten counterweight. The stainless steel ones are a cost cutting exercise. The tungsten ones are supposed to sound slightly better thanks to the smaller size of the tungsten weight producing less polar moment of inertia.

I have not compared the two.

Regards,
Frank.

Posted on: 04 January 2001 by Tony L

quote:
Did you remember to check which phono boards you're running, or did the crack dust on your counterweight take the evening in a different direction?

I checked, I am using the Rev 4 S boards that were recapped at the same time as my preamp. I find they sound a little bigger, freer and are more involving than my rev 3 Ks. When Vuk commented on a absolute preference for the Ks I stuck 'em in for a week to check myself - I preferred the S boards even when put in cold.

I am sure my choice may be based as much on the different revision, and the age of the caps as much as any real preference for either type. Most good dealers have boards lying around, and some are pretty much prepared to do a straight swap, so if you get a XX1L I would go and listen yourself. I have heard dealers state preference for particular revisions, one local dealer seemed to reckon rev 3 or 5 boards are better than my rev 4s - did arouse my bullshit detector a bit.

My gut feeling as it is I suspect it is only just a subtle difference in loading between the K and S boards (it is either a resistor or a cap that is different), that it is probably just in effect a bit of a tone control. Try and hear both in your system.

Tony.

Posted on: 04 January 2001 by Joe Petrik

Thanks Tony.

I should get a pair of S boards just for completeness and to score extra FEPs. I've got an opportunity to try a couple of the Dynavectors and the U.S. DV rep himself said that most people prefer the S boards with Dynies, the XX-1L possibly being the exception.

Best to have the S boards on hand for that inevitable day an XV-1 shows up on my doorstep. Hey Frank, does Rega make an extra, extra real heavy counterweight?

Joe

Posted on: 04 January 2001 by Ron The Mon

Vuk,
It's not just about the length and circumference of your unit but also knowing how to use it.

Ron The Mon

Posted on: 04 January 2001 by Frank Abela

Joe

No. Anyway, I think you'd need extra tall spacers as well. I believe they're called 'stilts' in common parlance, or is it piles?

Seriously speaking, I've not tried an XV-1 in an RB900, but I don't really think that would be an effective pairing since it's so out of spec that it would be difficult to believe the other limitations of arm and deck would not outweigh the gains of the cartridge, good though the deck is.

A Te Kaitora, on the other hand, would fit much more snugly since it's also so much lighter than an XX-1L.

Regards,
Frank.

Posted on: 04 January 2001 by Joe Petrik

Frank,

quote:
A Te Kaitora, on the other hand, would fit much more snugly since it's also so much lighter than an XX-1L.

I just finished attending a 12-step program to put the Te Kaitora out of my mind -- and now you've set me back several weeks.

The XX-1L is good enough, the XX-1L is good enough, the XX-1L is good enough, the XX-1L is good enough, the XX-1L is good enough, the XX-1L is good enough...

Joe

Posted on: 04 January 2001 by Ron The Mon

Tony,
I appreciate your politeness and sense of starting a new thread (and thanks for the idea of the Kan poll). I intended on insulting no-one and am sorry it ended in name calling (BTW, I prefer being called a prick to ass----).

For the record; I have had in my possession at the same time three different size weights. I will get back on the exact grams though the heaviest is definitely more than 120. None have a groove and all are from circa 1985. I have used the Troika and Arkiv and even though they have a listed weight of less than the XX-1L, they have a third mounting screw and a lower tracking force. This equates to approximately the counterweight being in the same spot. According to conversation with Roy Gandy, the reason for the difference in the Rega "protractor" over others has little to do with geometry and everything to do with getting the countereight as close to the pivot-points as possible. Linn has changed the weight of their counterweights in the Ittok over the years to achieve the same results. Naim has also cleverly done so in the Aro with a lower center than the armtube. Roy has said that eliminating spacers results in better sound in his arms because VTA is less important than rigidity and counterweight position. The proper way to compensate for incorrect VTA in a Rega table is to use different thickness felt mats (Rega sell these after-market also). I used to keep a thick mat on hand for playing thin records though I tired of the hassle.
Start from scratch; Use the Rega "protractor" to set the position of cartridge in the "headshell". If you don't have one, the diamond with tracking force applied should be at the front hole on top (where Elys third screw goes). Again, don't use spacers, use a thicker Rega mat to compensate. Finally, set tracking force so that the counterweight is as close to pivot point without touching it, and adjust remainder with the dial. If the dial remains at zero it's alright as it is a wound spring which applies force even at the zero setting. This requires a tracking force scale, many of which are inaccurate, so fine tune by ear. BTW, moving the position of a cartridge's length, if it has a lot of hours on it, can result in a shorter lifespan or damaged records.

Sincerely,
Ron The Mon

[This message was edited by Ron The Mon on THURSDAY 04 January 2001 at 23:18.]